Ultrasonic Bonding Tool Protrusions Prevent Resin Adhesion

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Solution Overview

Problem

Ultrasonic bonding of synthetic resin sheets in layered batteries is hindered by adhesion of molten resin to knurled protrusions on the horn and anvil, leading to the workpiece becoming affixed, which complicates the joining process.

Innovation Solution

The ultrasonic bonding tool features quadrangular pyramid protrusions with apex angles between 110-130°, which suppress adhesion by reducing localized biting into the resin sheets and minimizing the force component that causes adhesion during resin shrinkage, and optionally includes a non-adhesive coating for further reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If knurled protrusions are used on the ultrasonic bonding tool, then bonding strength is improved, but molten resin adheres to the protrusions causing workpiece affixation

Engineering Contradiction:
Improvebonding strengthVSAvoidresin adhesion to tool
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The invention changes the geometric parameters of the protrusions by specifying a particular apex angle range (110-130 degrees). This parameter modification alters how the protrusions interact with the resin material during ultrasonic bonding, reducing adhesion while preserving bonding effectiveness.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies a non-adhesive coating to the surface of the protrusions. This creates a localized property difference where the coating layer prevents resin adhesion while the underlying protrusion structure maintains bonding capability.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If portions devoid of heat-resistant layer are formed to enable joining, then ultrasonic bonding becomes possible, but adhesion to protrusions occurs during the process

Engineering Contradiction:
Improvejoinability of separatorsVSAvoidworkpiece affixation to tool
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The invention modifies the geometric parameters of the protrusions (apex angle of 110-130 degrees) to change the interaction dynamics between the tool and molten resin, thereby preventing adhesion while maintaining the ability to join separators with and without heat-resistant layers.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The non-adhesive coating acts as an intermediary layer between the protrusion surface and the molten resin. This coating prevents direct contact and adhesion between the resin and tool surface, allowing the bonding process to proceed without workpiece affixation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If protrusions bite into synthetic resin sheets for bonding, then bonding strength increases, but adhesion force increases causing workpiece affixation

Engineering Contradiction:
Improvebonding strengthVSAvoidadhesion force
Core Design Contradiction:
StrengthVSForce

Solution Approach 1:

The invention optimizes the apex angle parameter of the protrusions to a specific range (110-130 degrees). This geometric parameter change reduces the adhesion force component while preserving sufficient biting action to achieve strong bonding between resin sheets.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The non-adhesive coating is applied locally to the protrusion surfaces where contact with molten resin occurs. This creates a localized non-adhesive zone that eliminates workpiece affixation while maintaining the protrusions' ability to bite into and bond resin sheets.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration effectively prevents the workpiece from adhering to the tool, enhancing bonding efficiency by minimizing adhesion and ensuring reliable separation of the resin layers without compromising the breaking of heat-resistant layers.

Implementation Method 1

ultrasonic bonding tool provided with protrusions used on a horn side of an ultrasonic bonding device

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Implementation Method 2

protrusions shaped as quadrangular pyramids having a flat top surface, and each of the protrusions has an angle within a range of 110°-130°, with the angle being an apex angle formed by two mutually opposite side surfaces

Methodology Applied
Scientific EffectImpact force: Impact Force

Implementation Method 3

protrusions shaped as quadrangular pyramids having a flat top surface, and each of the protrusions has an angle within a range of 110°-130°, with the angle being an apex angle formed by two mutually opposite side surfaces from among four side surfaces

Methodology Applied
Scientific EffectMechanical force: Mechanical Force

Data Source

PatentEP3563963B1Tool and method for ultrasonic bonding
Publication Date: 2021.12.15 ENVISION AESC JAPAN LTD
  • EP3563963B1 patent drawingFigure 1~2
  • EP3563963B1 patent drawingFigure 3~5
  • EP3563963B1 patent drawingFigure 6~7

AI summary

A tip (24) on which a plurality of protrusions (31) are formed in a regular pattern is provided to a horn (23) side of an ultrasonic bonding device (21). Each of the protrusions (31) is shaped as a square pyramid having four side surfaces (31a, 31b, 31c, 31d) and a flat top surface (31e). An apex angle (α) formed by two mutually opposite side surfaces is greater than 90°, e.g., is 120°. When two separators (1) of a battery cell are joined together, a force with which the separators (1) adhere to the protrusions (31) is weak, and the separators (1) do not adhere to the horn (23).